Question

DNA damage brought on by a variety of natural and artificial agents elicits a wide variety of cellular responses. In addition to the activation of DNA repair mechanisms, there can be activation of pathways leading to apoptosis (programmed cell death) and cell-cycle arrest.

Part A

Why would apoptosis and cell-cycle arrest often be part of a cellular response to DNA damage?

Cell-cycle arrest and apoptosis consume less energy.

Many cells do not have DNA repair mechanisms.

Cell-cycle arrest and apoptosis are milder ways to cope with mutations.

DNA repair mechanisms often cannot reduce the impact of mutations.

(2) The process of error correction of mismatched bases from the end of a growing polynucleotide that is carried out by DNA polymerases is called ________.